Refrigerating apparatus



Jan. 7, 1941. D. E. DASHER REFRIGERATING APPARATUS Filed Aug. 19, 1938 2Sheets-Sheet l NVEN OR ATTORNEY.

Jan. 7, 1941. D. E. DAsHER REFRIGERATING APARATUS Filed Aug. 19, 1938 2Sheets-Sheet 2 INVENTOR. CDM Q G/JJA/ /Ww/ Z TORNEY. v

atented Jan. 7, 1941 PATENT or-FICE REFRIGERATING APPARATUS Don E.Dasher, Dayton, Ohio, assignor to General Motors Corporation, Dayton,hio, a corporation of Delaware Application August 19, 1938, Serial No.225,763

10 Claims.

This invention relates to refrigerating apparatus and more particularlyto control means therefor.

Recently, in order to control the flow of liquid refrigerant from thehigh pressure portion of the refrigerating system tothe low pressureportion, it has become common practice to employ an elongated passage.Such passages have been made in several different ways, one form beingsimply along tube of very small diameter, others employ interttingcylinders provided with helical grooves, while others employ porousplates. It has been found, however, that such passages if designed forhigh room temperatures allow too great an amount of liquid'refrigerantto flow from thc high side to the low side under cold room temperaturesand if designed for cold room temperatures, provide too great arestriction and insuiiicient flow at high room temperature.

It is an object of my invention to provide an elongated passage whichcan automatically change its resistance in response lto pressure and/ortemperature variations.

It is a further object of my invention to provide a simple, inexpensiveform of elongated passage which is capable of automatically changing itsrestriction to flow according to the refrigerant pressure Within thesystem and thus responsive to environment temperatures since therefrigerant pressures within the system, particularly in the highpressure portion of therefrigerating system, are in general responsivetothe room or environment temperatures.

It is still a further object of my invention to provide an elongatedpassage' for a refrigerating system between sheet metal walls of acurled assembly of two sheet metal portions which is capable of varyingthe amount of restriction of the passage by the amount of curvature ofthe curled lo assembly.

Further objects and advantages of the present invention will be apparentfromthe following description, reference being had to the accompanyingdrawings, wherein a preferred form of the present invention is clearlyshown.

In the drawings:

Fig. 1 is a representation of a refrigerating system, partiallydiagrammatic, embodying my invention;

passage member shown in Fig. 1; Fig. 3 is a cross sectional view takenon line 3--3 of Fig. 2; l Fig. 4 is a, cross sectional view taken online -4 of Fig. 2;

Fig. 2 is an elevational View of an elongatedl (Cl. 13S-46) Fig. 5 is across sectional view taken on line 5---5 of Fig. 2;

Fig. 6 is an elevational view of the passage member shown in Fig. 1after being wound into a spiral form;

Fig. 7 is an enlarged view of Fig. 4;

Fig. 8 is an enlarged view of Fig. 4 taken to represent the expansion ofa passage under high pressure conditions;

Fig. 9 is a representation of a refrigerating 10 system, partiallydiagrammatic, embodying a modified arrangement of my invention;

Fig. 10 is a view similar to Fig. 9, omitting the refrigerant liquefyingunit, showing a modied positioning of the passage of my invention;

Fig. 11 is an elevational view of a modified form of the elongatedpassage member; and

Fig. 12 is an enlarged elevational view of the passage member as shownin Figs. 9 and 10.

Briefly, I have disclosed a refrigerating system 20 for a domesticlelectric: refrigerator having a sealed motor-compressor unit, a flatplate type condenser, an elongated passage member and a. sheet metalhousehold type of evaporating means connected in closed refrigerantcircuit by metal 25 tubing. The passage which controls the flow ofliquid refrigerant from the plate type condenser to the evaporatingmeans is formed of a long strip of thin metal which is provided with agroove. This strip of metal may then be folded upon itself 30 or asecond sheet of metal placed thereon, sealed at the edges, and rolledinto a spiral. One end of the groove is connected to the plate condenserand the other end is connected to the evaporating means. The operationof the motor-compressor 35 unit is controlled by a thermostatic switchaccording to the temperature ofthe evaporating unit.

Referring now'more particularly to the drawings, there is shown in Fig.1 a sealed unit 20, 40 containing a rotary compressor 22 directlyconnected to the rotor 24 of a split phase induction type electric motorprovided within the upper portion of the sealed unit. The sealedmotorcompressor unit discharges compressed refriger- 45 ant through asupply conduit 26 to the top of a vertically uted plate type condenser28, ordinarily positioned upon the rear wall of a domestic electricrefrigerator. The compressed refrigerant is cooled and liquefied withinthe plate condenser 50 28 and is collected in a header at the bottomthereof which header serves as a receiver.

'I'his liquid refrigerant is conducted by a conduit 3U to an elongatedpassage 32 located within the food compartment 34 of a domestic electric55 refrigerator '35 which is illustrated diagrammatically.- Theelongated passage 32 controls the flow of refrigerant to the plate typeevaporating means 36 which'is provided with an entrance for liquidrefrigerant at the bottom in the form of aheader which distributes theliquid refrigerant to refrigerant passages extending up f the side wallswhich terminate in headers 40.

The refrigerant in'the walls of the evaporating means evaporates underreduced pressure and is returned to the compressor through the returnconduit 42.

The operation of the sealed motor compressor unit is controlled by athermostatic switch means M which energizes the compressor-motorwhenever the temperature of the evaporating means reaches apredetermined high limit and deenergizes the compressor-motor wheneverthe evaporating means reaches a predetermined low temperature limit. Themotor-compressor unit is also provided with a starting relay 46 forenergizing and deenergizing the split phase starting winding at thebeginning and the end of each starting period. i

The elongated passage 32 is formed by providing a groove 50 in one endof a long strip of thin resilient sheetmetal 52. This groove 50 may beof any suitable shape, but as shown, is V-shaped and extends overslightly less than one-half the length of the strip. This strip may thenbe folded upon itself so that the fiat sheet portion closes the V-shapedgroove 50 and makes a triangularshaped passage 56 as best shown in Figs.3 and 4. The passage 56 may also be formed by an alternate method ofplacing a at sheet of metal upon :the sheet in which the groove isformed in order to close the V-shaped groove 50 thereby providing aV-shaped passage. A triangular-shaped passage is preferred since it isfound that such a passage is less susceptible to the clogging or thecollection of foreign matter therein. This folded sheet metal structure,or the structure consisting of two metal sheets, is then sealed alongits edges by soldering or preferably by roll welding.

'The elongated passage may also take the form as disclosed in Fig. 11.In this form the passage is formed by providing a hairpin-shaped groove60 in one end of a long strip of thin resilient metal. The metal stripmay be folded upon itself to close the open side of the groove 60, or aseparate metal sheet may be used, thereby providing an elongated passagebetween the metal sheets. This sheet metal structure is preferably rollwelded along its edges, as indicated at 6I, thereby 'sealing the same.That portion of the metal sheets between the hair pin loops forming thepassage are also sealed together, as indicated at 62, by roll welding orother suitable means. This central portion, however, is not sealedtogether throughout its entire length, but a portion 63 is leftpartially unsealed which will permit a variation in restriction or aby-passing of liquid through this section 63 when the pressure of thehigh side of the refrigeration system increases.

The sheet metal structure forming the elongated passage is then curledor rolled into a spiral form as shown in Fig. 6 with the sheet, in whichthe groove is formed, on the outside. The two open ends of the passage56 are each provided with connectors 58, one of which connects theentrance of the passage to the tube 30 extending from the plate typecondenser, While the exit of the passage'connects to the tube 60 whichextends to the evaporating means.

In the forms shown in Figs. 9, 10 and 12 a slightly modified arrangementof the elongated passage is shown. In this form the elongated passageconsists of a tubular member 10 having a small internal bor-e. A secondportion of the passage consists of a sheet metal structure 1I which isconstructed in a manner similar to that previously described in regardto the passage element 32. In this instance, however, the elongatedgroove 12 formed in one of the thin sheet metal strips is in the form ofa hairpin loop. The open side of the V-shaped groove 12 may be closed ina manner as heretofore described in regard to the elongated passage 32.In this instance the passage structure 1I is sealed around the edges bysoldering the same, or preferably by roll welding as indicated at 13.The central portion 'I4 between the parallel legs of the hair pin loopis not sealed so tightly as to prevent expansion of the hairpin loop,for the reason that it is desirable that this portion be permitted tovary in cross sectional area.

In Fig. 9 is shown an arrangement of a. capillary tube type restrictor'l0 and the sheet metal passage structure H wherein the high pressureliquid refrigerant line 30 enters one side oi' the hairpin loop 12 inthe passage structure 1|. The exit from the passage structure 'Ilconnects to .10. The exit from the capillary tube type passage connectswith the inlet of the evaporating means. In Fig. 10, there is shown anarrangement whereby the high pressure refrigerant line 30 first connectswith the capillary tube type passage 10, the sheet metal passagestructure 1| being on the end of the capillary tube 'I0 between the tubeand the inlet of the refrigerating means.

The sheet metal passage assemblies when constructed in accordance withthis invention have very definite advantages. In the lrst place, theinitial amount of restriction provided in the elongated passage may beobtained by controlling the size of the passage 56 during manufacture.Also, when the temperature of the environment in which the refrigeratingapparatus is placed increases, it is desirable that the passage be ableto pass a greater quantity of liquid than when the temperature of theenvironment is low. This is possible in the structure of this inventionbecause the thin metal sheets from which the passage is constructed areelastic. A pressure increase Within the refrigeration system will tendto expand the sheets as shown in Fig. 8, thereby increasing the size ofthe passage and decreasing its restriction to the flow of refrigerant orother iiuid therethrough. In this way, the passage is able to operate ina manner so as to automatically control the rate of ow through thepassage in response to pressure Variations within the refrigerationsystem.

When the passage assembly is curled 'with a small radius of curvature,the initial restriction provided in the passage may be controlled byvarying the radius of curvature and the amount of curl of the assembledsheet metal portions. This arrangement provides a highly sensitive wayof providing the proper amount of initial restriction through a passage.It is also possible for the curled passage structure to act in a mannerwhich bears a slight resemblance to the action of a Bourdon tube. Thus,when a refrigerant pressure within the system and particularly when therefrigerant pressure within the condenser is high, for example, when theroom temperature is high,4 the sheet metal product will tend to uncurlslightly and to provide a slight itt ttt

separation of the sheets by the bowing ofthe inther sheet as shown inFig. 8. This will also provide a means whereby the cross sectional areaor the passage will vary with the pressure in the lsystem in order toprovide a variation inthe amount of restriction provided by theelongated passage.

The passage member, as disclosed in Fig. 2 and consisting of a singlepassage extending from one end to the other of the sheet metalstructure, may vary throughout its entire length in cross sectionalarea. The function of the passage is to permit a regulateddlow oi fluid'therethrough according to the initial restriction placed in the passageduring manufacture. If the resistance of the passage were fixed to meetthe refrigeration requirements of the refrigerator when in a lowtemperature environment, this same passage would pass too smallv aquantity of refrigerant when the temperature of the environment of therefrigerator increased. However, the functioning of fthe passage of myinvention will be to permit an increased flow of liquid refrigerantthrough the passage when the refrigerant pressure on the high side oftheI refrigeration system increases. The reduced restriction of thatportion of the passage which connects with the high pressure refrigerantline will be effective to permit a greater now of liquid refrigeranttherethrough. The length of the passage which will be increased in crosssectional area will be indeterminate and, if necessary, may bethroughout the entire length of the passage.

The sheet metal passage structure ll or 32 can be formed from two sheetsof metal each having a different coeilicient of expansion, therebyproviding an element which will be sensitive to temperature variationslike any bimetal element. The metal 4having the greater coefiiclent ofexpansion is placed on the inner side of the spiral sheet metal passageassembly, in which instance'as the temperature of the environment inwhich the passage is placed increases the spiral sheet metal elementwill reduce the degree of its curvature thereby lessening the degree ofrestriction oiered by the passage. This temperature responsive elementmay be used in any arrangement in place of the pressure responsiveelement.

lin the arrangement of the passage elements 'lil and li as shown in Fig.the sheet metal passage is constructed ol two sheets of metal havingdifferent coefficients of expansion and thus is responsive to thetemperature of its environment. In this instance the temperatureenvironment is the temperature of the cooling means. Since thetemperature responsive sheet metal passage element is connected betweenthe capillary tube type passage 10 and the inlet of the cooling means,the pressure within the passage structure 1| is substantially that ofthe evaporating means which is relatively low and substantiallyconstant. This arrangement of the passage elements thus provides asystem wherein a portion of the passage is substantially responsive totemperature only.

lin the arrangement of the passagev elements 10 and 1I as disclosed inFig. 9 the portion of the passage, capable of having its restrictionvaried,

is responsive to pressure variations of the high pressure side of therefrigeration system since the inlet of the passage is connecteddirectly to the high pressure liquid line 30. The sheet metal passageelement may, however, be made responsive to both temperature andpressure if the sheets of metal of the passage structure are such thatthey have ditlerent coefdcients of expansion. This application is acontinuation in part of my application for Flow restrictors, Serial No.61,569, led January 30, 1936.

While the form o1' embodiment of the invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scope oi the claims whichfollow.

What is claimed is as follows:

1. Means forming an elongated passage for controlling the flow of ailuid comprising an elastic metallic structure formed of twosuperimposed elastlc thin metal strip portions, said superimposed stripportions being sealed together at their edge portions but having a broadsubstantial expanse in the central portion unconnected except at theedge portions as stated, one of said strip portions having its innerface grooved to; provide an elongated passage between the Sheets, thecentral portions of said strip portions being movable to permit varyingdegrees of separation to enlarge the cross-sectional area of portions ofthe elongated passage.

2. Means forming an elongated passage for controlling rthe flow of afluid comprising an elastic metallic structure formed of twosuperimposed elastic thn metal strip portions, said superimposed stripportions being sealed together at their edge portions but having a broadsubstantial expanse in the central portion unconnected except at theedge pontions as stated, one of said strip portions having its innerface grooved to provide an elongated passage between the sheets, thecentral portions of said strip portions being movable to permit varyingdegrees of separation to enlarge thevcross-sectional area of portions ofthe elongated passage, said superimposed strip portions being curled insuch a manner as to cause the structure to assume varying degrees ofcurvature and restriction under varying fluid pressures in said passage.

3. Means forming an elongated passage for controlling the flow of afluid comprising an elastic metallic structure formed oi twosuperimposed elastc thin metal strip portions, said superimposed stripportions being sealed together at their edge portions but having a broadsubstantial expanse in the central portion unconnected except at theedge portions as stated, one of said strip portions having its innerface grooved to provide an elongated passage between the sheets, thecentral portions of said strip portions being movable to permit varyingdegrees of separation to enlarge the cross-sectional area of portions ofthe elongated passage, said superimposed strip portions being ofdifferent metals having a different rate of thermal expansion, saidbimetal strip portions causing said structure to curl in varying degreesaccording to the temperature of the structure to vary the crosssectional area of portions of the elongated passage.

4. Means forming an elongated passage for controlling a iiuid comprisinga curled elastic metallic structure, said structure having wall portionsprovided with means forming therein an elongated passage through whichthe fluid passes, said structure being curled and uncurled in the mannerof a Bourdon tube by pressure variations within the elongated passage tovary the restriction of the passage.

5. Means' forming an elongated passage for controlling a :fluidcomprising a curled elastic metallic structure, said structure havingwall portions provided with means forming therein an elongated passagethrough which the fluid passes, said structure being curled to a greateror lesser degree in the manner of a Bourdon tube according to pressurevariations within the elongated passage, the restriction of said passagebe-l ing established by the degree of curling of said structure.

6. Means forming an elongated passage comprising a bimetal strip havingrelatively iiat passages formed within the strip, said strip beingformed of diierent metals bonded together, said different metals havingdiierent rates oi thermal expansion causing the strip to curl and uncurlwith changes in temperature, the restriction of said passages beingestablished by the degree of curling of the strip.

7. Means forming an elongated passage comprising a bimetal strip havingpassages formed within the strip, said strip being formed of differentmetals bonded together, said strip being also provided with a by-passfor said passages, said by-pass being opened when the strip uncurls andclosed when the strip is fully curled, said diierent metals havingdifferent rates of thermal expansion causing the strip to curl anduncurl with changes in temperature.

8. Means forming an elongated passage corriprising a strip havingpassages formed within the strip, said strip being formed of twosuperimposed metai sheets bonded together. said strip beingprovided-with a by-pass for said passages, said by-pass being openedwhen the strip uncurls and closed when the strip is fully curled, saidstrip being constructed and arranged for uncurling when the pressurewithin the passages is high and for curling when the pressure Within thepassages is low.

9. A restrictor formed of superposed secured together sheet metalmembers, a portion of one of said sheet metal members being directedoutwardly away from a portion of the other sheet metal member to providewalls of a continuously open passage between the members having apredetermined cross-sectional area, said sheet metal members being sosecured together and arranged with respect to one another that saidportion of one of said members is movable in response to certainconditions relative to said portion of the other or said members tochange the cross-sectional area o! the passage.

l0. A restrictor comprising a curled elastic structure formed ofsuperposed secured together sheet metal members, a portion of one oi'said sheet metal members being directed outwardly away from a portion ofthe other sheet metal member to provide walls of a continuously openpassage between the members having a predetermined cross-sectional area,said portion oi' one of said members being movable relative to saidportion of the' other of said members forV chang- -ing thecross-sectional area of the passage, and

said structure being curled and uncurled in the manner of a Bourdon tubeto cause said relative movement of said portions oi' said members.

DON E. DASHER.

